The flow cytometry laboratory consists of two FACScans (HP9000) with dual cartridge Bernoulli discs, FACStar Plus (HP9000), a MicroVax II, and a Macintosh II and a Macintosh IIcx. All are networked. Several printers including a Tetronic color printer and LNO3 are available. There are 3 FTE flow cytometer operators capable of doing surface markers and/or cell cycle analysis and cell sorting. A major activity this past year has been the investigation of CD5 and CD20 expression in B chronic lymphocytic leukemia. In addition, we evaluated the serological distribution of the common CLL antigen and its cell cycle relationship. An evaluation of whole blood lysis was completed as part of our studies for individual members of kindred with familial B-CLL. A collaborative review on quantitative flow cytometry was completed. We participated in the NYAS CD5 B-cell meeting and two abstracts were submitted to the International Society of Analytical Cytometry and we attended the Sixth Annual Meeting Clinical Applications of Cytometry. We also participated in M. Potters's meeting on B cell neoplasm. Software programs for data display (LAP, CAP, DCRT) were evaluated and FDAPLOT for the composite display of two parameter contour plots was completed. Our present efforts concern the purification, fractionation, sorting and analysis of blood B lymphocytes and B-CLL lymphocytes to be used in conjunction with PCR methods. Presently we are able to sort sufficient B cells for a PCR analysis of monoclonality. We need to add a separate work station in the flow lab and plan to continue to develop software to meet our needs. We stil would like to add digital image analysis to complement our cell analysis. The development of FCM consortium is underway.